Blocking scam calls

[Mr Badger]

Are there any good products for blocking scam telephone calls on a land line? Rather than nuisance marketing callers we're talking about actual scammers pretending to be from your bank or similar.

This is for an elderly person who has never owned a computer or smartphone and unfortunately seems to believe official sounding calls telling them there has been fraud on their card and the like.

 

[Mr Badger]

So the consensus is that these call blocking phones are actually worth having then.

Aside from the features and quality of the phone, does anyone know if there is any difference in the "trueCall call blocking technology" between the various BT models or do they all work the same?